refs #7674: now provides layout feature so that visible fields collapse and fill any hidden fields. A more subtle enhancement/fix is that some rules now cascade - e.g., if a clear rule clears a field A and then if a hide rule hides a field B if field A is empty, then field B will get hidden when field A gets cleared. In order words, the rules are cascaded/chained. (If this doesn't make sense don't worry about it. :)

Again reviewed by Radek Bartoň, who added the ingenious, original
translation module import to template files.
Bumping version, since this is going to be backwards-incompatible anyway.
And we'll aim at translated doc-strings for all registered configuration
options; 1st time I see this one, let's see, how/where this works.